The present invention relates to an underwater projectile and, more particularly, to a supercavitating underwater projectile that is constructed to enlarge the naturally occurring cavitation bubble to reduce hydrodynamic drag.
In anti-torpedo or anti-mine systems or the like, an underwater projectile is fired from a gun to intercept and/or destroy the torpedo or mine. While such underwater projectiles have been shaped to form a cavitation void around the projectile in the water to reduce hydrodynamic drag, the velocity, size and range of the projectiles have been limited by such drag. Accordingly, a need has arisen for a new and improved underwater projectile for anti-torpedo or anti-mine use or the like which has increased range and/or lethality. The supercavitating underwater projectile of the present invention meets this need.
The supercavitating underwater projectile of the present invention is constructed to increase the velocity of the projectile when fired, and thus its lethality upon impacting the target, through supplemental propulsion and the expansion of the cavitation bubble around the projectile, allowing for a larger projectile with reduced hydrodynamic drag.
This is accomplished by providing a small rocket motor in the projectile which is ignited by the hot gases of the gun powder charge of the gun system when fired to eject the projectile from the gun barrel. The ignition of the rocket motor provides additional axial thrust to increase the velocity of the projectile in the water and thus its lethality and/or range. The projectile comprises an internal ventilation system for venting some of the propellant combustion gases to the exterior of the projectile near the front or nose portion thereof. The vented combustion gases serve to expand the naturally occurring cavitation bubble formed as the projectile travels through the water to reduce hydrodynamic drag. In this manner, the velocity, range and lethality of the projectile are increased. Also, larger projectiles can be employed.